Standby Power and Vampire Load Cost Calculator
TL;DR: Standby Power 50W × 24h = 1.20 kWh/day = $0.19/day, $5.76/month, $69.12/year at $0.16/kWh — 公式 ▸
kWh = watts ÷ 1000 × hours
cost = kWh × rate per kWh
50 ÷ 1000 × 24 = 1.200 kWh/day
1.200 × 0.16 = $0.19/day| Period | Energy | Cost |
|---|---|---|
| Per hour | 0.050 kWh | $0.01 |
| Per day | 1.20 kWh | $0.19 |
| Per month (30 days) | 36.0 kWh | $5.76 |
Source: ProEnergySaver, calculated at $0.16/kWh (US average). Rates cross-checked against EnergyStar, DOE and Ofgem published figures.
Add up the hidden cost of always-on electronics across your home. Adjust the wattage, runtime and your own electricity rate below — every figure updates instantly in your browser, and nothing you type is sent anywhere.
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How this cost is calculated
The formula is kWh = watts ÷ 1000 × hours, then cost = kWh × your rate per kWh. Standing charges and tiered or time-of-use pricing are billed separately by your supplier, so treat these numbers as the marginal cost of running this appliance rather than a full bill.
For the full breakdown with regional price tables, read the detailed guide, or estimate your whole household on the home electricity bill calculator.
Frequently asked questions
How much does a 50W standby load cost?
At $0.16/kWh, it costs about $5.76 per month or $69.12 per year when left on continuously.
Which devices use the most standby power?
Game consoles, set-top boxes, desktop computers and older audio equipment are common high standby users.
Do smart power strips save money?
They can when they fully switch off groups of devices that otherwise draw power for many idle hours.
Power saving devices: do electricity saving boxes actually work?
Does Power Saver Pro electricity saving box actually save electricity?
No. For fake plug-in boxes (StopWatt, Power Saver Pro), savings will be 0 kWh ($0.00) because they do not reduce active power. Residential meters only measure active power (kWh), so improving power factor at home changes nothing on your utility bill. For legitimate power-saving devices (smart power strips, programmable thermostats, timers), use Daily kWh Reduction = (Original Watts x Original Hours - New Watts x New Hours) / 1000, and Monthly Savings ($) = Daily kWh Reduction x 30 Days x Utility Rate per kWh. Example: a TV setup (TV, soundbar, game console) drawing 30 Watts on idle/standby for 20 hours a day is 0.60 kWh/day = $2.88/month at $0.16/kWh. A water heater saving 500W x 1.5h is 0.75 kWh/day = $3.60/month. Verify real-world consumption with a physical power meter such as a Kill A Watt meter.
Is StopWatt energy saving device scam or legit how much does it save?
StopWatt is a complete scam. It saves exactly $0.00. Testing by consumer protection agencies shows it slightly increases your bill because the internal LED draws power. Red flags: "Stabilizes voltage & power factor" (false for residential billing), "Cleans dirty electricity" (marketing buzzword), "Endorsed by Elon Musk / Shark Tank" (100% fake deepfakes), "Cuts bills by 60%" (independent teardowns show only a cheap capacitor and an LED inside). Real savings come from adjusting the thermostat, lowering the water heater to 120°F (49°C), and using smart power strips to eliminate phantom standby loads.
To price a genuine saving, use Daily kWh = Watts × Hours ÷ 1000 in the Real kWh Savings Calculator.
Want regional price tables, savings tips, and worked examples for this appliance?
Read the full guide →More cost calculators
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